Systemic Primary Carnitine Deficiency Presenting With Substantia Nigra and Basal Ganglia Injury: A Case Report.

Area of Science:

• Biochemistry
• Genetics
• Neurology

Background:

• Systemic primary carnitine deficiency (SPCD) is a rare metabolic disorder affecting fatty acid oxidation.
• Impaired energy production in SPCD can lead to hypoglycemia, encephalopathy, and sudden death.
• Current newborn screening (NBS) protocols for SPCD lack standardization, risking missed diagnoses.

Purpose of the Study:

• To report a case of SPCD missed by NBS, leading to severe neurological sequelae.
• To emphasize the importance of early diagnosis and management of SPCD.
• To advocate for standardized NBS criteria for SPCD.

Main Methods:

• Case report of a 1-year-9-month-old girl with clinical presentation suggestive of a fatty acid metabolism disorder.
• Diagnostic workup included biochemical tests (serum carnitine levels, glucose, ammonia) and genetic analysis (SLC22A5 mutation).
• Neuroimaging (MRI) was used to assess brain involvement, and treatment response was monitored.

Main Results:

• The patient presented with hypoketotic hypoglycemia, hyperammonemia, and myocardial hypertrophy, despite normal NBS results.
• Confirmed diagnosis of SPCD with homozygous SLC22A5 mutation and critically low carnitine levels.
• Developed basal ganglia damage and dystonia, requiring ECMO and L-DOPA treatment, with partial recovery.

Conclusions:

• Basal ganglia damage is a severe complication of SPCD, even in cases with initially normal NBS.
• Prompt L-carnitine supplementation and early ketone measurement are vital in suspected fatty acid metabolism disorders.
• Standardized NBS protocols with defined carnitine cutoff values are essential for early SPCD detection and prevention of neurological damage.